1. Field of the Invention
The present invention relates to a water pump applied to a vehicle. More particularly, the present invention relates to a water pump for a vehicle in which an electrical clutch is applied inside a pump body.
2. Description of Related Art
Vehicle manufacturers are currently attempting to improve fuel efficiency as well as exhaust gas quality through research processes thereof, and they have specifically increased a catalyst amount of the exhaust system or the capacity of the EGR cooler so as to satisfy emission regulations.
A coolant passage is formed between a cylinder block and a cylinder head of an engine, and a water pump circulates a coolant through the coolant passage so as to prevent overheating of the engine and sustain a regular temperature.
The water pump supplying the coolant is operated by a power transferred through a belt and circulates the coolant “radiator→cylinder→cylinder head→radiator” so as to prevent the engine from being overheated.
An impeller of the water pump is rotated by the rotation torque transferred from the engine through the belt to pump the coolant to the cylinder block, and the rotation speed of the impeller is 1.2-1.6 times that of the crankshaft.
The water pump is continuously operated by the belt after a starting of an engine to circulate the coolant regardless of a warming up condition of the engine and a coolant condition.
Accordingly, a fuel consumption and an exhaust gas are stabilized in a condition that the engine is warmed up. However, in a condition that the cold engine is started, a warming up is delayed by a circulation of the cold coolant such that a friction of an engine operating component is increased and abrasion thereof is increased.
Also, since combustion efficiency is decreased to warm up a cold engine, fuel consumption is increased, an activation time of a exhaust gas catalyst is delayed, and harmful material in the exhaust gas is increased.
However, as the water pump is always operated, there is a problem that the power of the crankshaft is lost in such a manner that the output of the engine is deteriorated and the fuel efficiency becomes lower.
Since the power is not disconnected from a crank shaft to the water pump, those problems as stated above are occurred.
The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.